203 results on '"Soon Jae Lee"'
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2. Influence of Arc Brazing Parameters on Microstructure and Joint Properties of Electro-Galvanized Steel
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Soon Jae Lee, Ashutosh Sharma, Do Hyun Jung, and Jae Pil Jung
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gas metal arc brazing ,zinc-coated steel ,filler metal ,tensile shear strength ,microhardness ,Mining engineering. Metallurgy ,TN1-997 - Abstract
Arc brazing of zinc-coated steel (EG, Electro-galvanized steel) using Cu-3 wt%Si filler metal was performed. The influence of arc current and brazing speed on the bonding properties of the joint, such as bead characteristics, arc penetration, joint hardness, and tensile shear strength were evaluated. The microstructural characteristics of the joint were examined by scanning electron microscopy (SEM) and the compositional information was revealed by energy dispersive spectroscopy (EDS). The throat thickness varies inversely with the brazing speed. The EG joint shows the formation of Fe2Si phases, which result in higher microhardness than the base metal. The tensile samples were fractured in base metal, while minor bead cracks developed in the samples brazed at 80 cm/min-80 A, 60 cm/min-70 A, 70 cm/min-70 A.
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- 2019
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3. Facultative mycorrhization in a fern (Struthiopteris spicant L. Weiss) is bound to light intensity
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Thais Guillen-Otero, Soon-Jae Lee, Dietrich Hertel, and Michael Kessler
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Struthiopteris spicant ,Facultative mycorrhizal plant, mycorrhizal status, fern, arbuscular mycorrhizal fungi ,ITS ,Greenhouse experiment ,Light ,Nutrients ,Botany ,QK1-989 - Abstract
Abstract Background The establishment of mycorrhizal relationships between a fungus and a plant typically enhances nutrient and water uptake for the latter while securing a carbon source for the fungus. However, under a particular set of environmental conditions, such as low availability of light and abundant nutrients in the soil, the resources invested in the maintenance of the fungi surpass the benefits obtained by the host. In those cases, facultative mycorrhizal plants are capable of surviving without symbiosis. Facultative mycorrhization in ferns has been overlooked until now. The present study measured the response of Struthiopteris spicant L. Weiss, and its root-associated fungi to different levels of light and nutrient availability in terms of growth, mycorrhizal presence, and leaf nutrient content. This fern species exhibits a great tolerance to variable light, nutrient, and pH conditions, and it has been found with and without mycorrhizae. We conducted a greenhouse experiment with 80 specimens of S. spicant and three factors (Light, Phosphorus, and Nitrogen) resulting in eight treatments. Results We found a significant influence of the factor light on fungal community composition, plant biomass, and nutrient accumulation. Departing from a lack of colonization at the initial stage, plants showed a remarkable increment of more than 80% in the arbuscular mycorrhizal fungi (AMF) richness and abundance in their roots when grown under high light conditions, compared with the ones in low light. We also observed an upward trend of C:P and C:N ratios and the above- and belowground biomass production when AMF abundance increased. Furthermore, the compositional analysis of the whole fungal communities associated with S. spicant roots revealed clear differences among low-light and high-light treatments. Conclusions This study is the first to investigate the importance of light and nutrient availability in determining fern-AMF relationships. We confirmed that Struthiopteris spicant is a facultative mycorrhizal plant. The composition and diversity of AMF found in the roots of this fern are strongly influenced by light and less by nutrient conditions. Our study shows that ferns respond very sensitively to changes in environmental factors, leading to shifts in the associated mycorrhizal communities.
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- 2024
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4. Revolutionizing Roadways: High-Performance Warm Mix Asphalt Binder with Trinidad Lake Asphalt and Recycled Tire Rubber
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Shyaamkrishnan Vigneswaran, Jihyeon Yun, Moon-Sup Lee, Kyu-Dong Jeong, and Soon-Jae Lee
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Trinidad Lake asphalt (TLA) ,crumb rubber modifier (CRM) ,leadcap (LC) ,high-performance ,sustainable pavement engineering ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This study investigates the transformative effects of incorporating Trinidad Lake asphalt (TLA), crumb rubber modifier (CRM), and the warm mix additive leadcap (LC) into petroleum-based asphalt binder PG 64-22. Our results show that LC significantly reduces binder viscosity, leading to easier application and lower energy consumption, especially when combined with TLA and CRM. The addition of TLA and CRM enhances rutting resistance, with notable improvements in both pre- and post-aging conditions, particularly in formulations combining PG 64-22, 20% TLA, and 10% CRM. These formulations exhibit superior performance metrics, such as increased percentage recovery (% rec) and reduced non-recoverable creep compliance (Jnr), indicating improved flexibility and deformation resistance. Furthermore, LC balances increased rigidity and susceptibility to fatigue cracking from higher TLA and CRM levels, respectively. These modifications also promote environmental sustainability by reducing energy usage and emissions during production and paving. This study highlights LC’s critical role in advancing high-performance, eco-friendly warm mix asphalt binders, offering valuable insights for sustainable pavement engineering and setting a new benchmark for advanced asphalt technologies.
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- 2024
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5. Optimizing Asphalt Binder Performance: The Synergistic Impact of Trinidad Lake Asphalt (TLA) and Crumb Rubber Modifier (CRM)
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Shyaamkrishnan Vigneswaran, Jihyeon Yun, Moon-Sup Lee, and Soon-Jae Lee
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TLA ,CRM ,Superpave test ,MSCR ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This research investigates the synergistic impact of Trinidad Lake Asphalt (TLA) and Crumb Rubber Modifier (CRM) on the performance characteristics of PG 64-22 asphalt binder. Employing Superpave test analysis and Multiple Stress Creep Recovery (MSCR) testing, our study reveals that the incorporation of TLA significantly elevates the viscosity of the binder due to its high asphaltene content. This viscosity enhancement translates to increased stiffness and durability of the asphalt binder. Furthermore, CRM contributes to improved elasticity and deformation resistance, counterbalancing the stiffness induced by TLA. Our results indicate that the combined use of TLA and CRM not only boosts viscosity but also mitigates stiffness, thereby enhancing the binder’s resistance to rutting, especially post-aging. However, an elevated concentration of TLA increases the risk of fatigue cracking, a concern effectively alleviated through the integration of CRM. At a critical temperature of −12 °C, Bending Beam Rheometer (BBR) tests demonstrate that TLA augments stiffness while CRM enhances low-temperature flexibility. This study underscores the necessity of optimizing TLA and CRM ratios to achieve a balance between enhanced performance and practical feasibility. The findings highlight the potential of TLA and CRM to substantially improve asphalt binder performance, contributing to the longevity and resilience of pavement structures.
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- 2024
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6. Enhancing Asphalt Binder Performance and Storage Stability with Trinidad Lake Asphalt (TLA)
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Shyaamkrishnan Vigneswaran, Jihyeon Yun, Hyunhwan Kim, Moon-Sup Lee, and Soon-Jae Lee
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TLA ,viscosity ,rutting resistance ,fatigue resistance ,low-temperature performance ,storage stability ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
This study delves into the transformative effects of Trinidad Lake Asphalt (TLA) on asphalt binders, revealing significant improvements in various performance metrics. Our findings indicate that TLA substantially increases binder viscosity and enhances rutting resistance, as evidenced by elevated G*/sin δ values in both original and RTFO-aged states. TLA-modified binders demonstrate superior rheological properties, including improved Jnr and percentage recovery, indicating enhanced resistance to permanent deformation and reduced fatigue cracking. However, an increase in TLA content correlates with higher G*·sin δ values, suggesting a trade-off with fatigue resistance and a higher susceptibility to cracking. Additionally, while TLA initially improves binder flexibility at low temperatures, excessive content can increase stiffness, adversely affecting stress relaxation properties. Notably, TLA enhances storage stability, ensuring minimal phase separation and excellent homogeneity. These insights underscore the need for the precise control of TLA content to optimize pavement durability. Future research should focus on fine-tuning TLA incorporation with additives like crumb rubber to maximize the structural integrity and longevity of asphalt pavements.
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- 2024
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7. Laboratory Evaluation of Storage Stability for Asphalt Binder Modified with Crumb Rubber and Styrene–Isoprene–Styrene Depending on Evaluation Factors and Blending Condition
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Jihyeon Yun, Shyaamkrishnan Vigneswaran, Hyunhwan Kim, Moon-Sup Lee, and Soon-Jae Lee
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CRM ,SIS ,storage stability ,SI ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
Modified asphalt binders are still considered important in asphalt pavement. However, the comprehensive use of various modifiers is limited due to storage stability issues. Moreover, there is a scarcity of detailed analyses regarding the degree of separation for asphalt binders among each method despite the utilization of various methods to assess the storage stability of binders. Therefore, a comprehensive analysis was conducted to assess the storage stability of asphalt binder modified with a crumb rubber modifier (CRM) and styrene–isoprene–styrene (SIS), utilizing five evaluation factors following the ASTM D7173 guidelines based on four mixing methods (A: high-shear mixing method, B: low-speed agitating method, C: high-shear mixing method + low mixing method, D: low-speed agitating method + low mixing method). To produce the modified asphalt binder, the proportions of the CRM were 5% and 10% for each binder, and 10% SIS was added to all binders. The results in this study convey that (1) the addition of the modifier led to an increase in G*/sin δ with different mixing methods, but using mixing methods (C and D) for a relatively long time resulted in a lower G*/sin δ, indicating suboptimal performance; (2) through the multiple stress creep recovery (MSCR), rheological properties of Jnr and % rec exhibited trends similar to G*/sin δ evaluation, highlighting an improved elastic recovery with a higher modifier content; (3) storage stability assessment revealed consistent trends in high-shear mixing groups (A and C), while low-speed mixing groups (B and D) exhibited an elevated separation index (SI), suggesting a sensitivity to modification conditions; (4) evaluation using the MSCR method indicated that % rec with a 3.2 kPa load is effective for the sensitive assessment of binder storage stability and Jnr showed a limited sensitivity across varying loads, advocating for % rec for precise evaluation; and (5) despite permitting various tests, achieving consistent results remains challenging. Future research should explore diverse modifiers and optimal evaluation methods to enhance knowledge of binder behavior and separation dynamics.
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- 2024
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8. Plant biotype interacting grazing activity shapes grassland ecosystem functions
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Li Wang, Shou‐Jiang Feng, Dandi Sun, Junying Wang, Yijia Wang, Soon‐Jae Lee, Peina Lu, and Yantai Gan
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bulk density ,carbon cycling ,grassland ecosystem services ,microbial community diversity ,plant composition ,soil physiochemical property ,Ecology ,QH540-549.5 - Abstract
Abstract Grasslands play an essential role in maintaining the health of planet Earth, but many grasslands have lost their ecosystem services due to unsustainable management practices, such as overgrazing. Little is known about how grazing activity interacts with plant biotypes, impacting grassland ecosystem services. Here, we (1) assessed the relative performance of five plant biotypes in response to grazing activities and (2) determined the effectiveness of grazing exclusion in enhancing soil physiochemical properties in grasslands. The synthesis of 39,214 observations on plant‐, soil‐, and anthropogeny‐related factors from 88 published studies revealed that grazing exclusion increased aboveground plant biomass accumulation by 100.4% (±4.2 SE), belowground biomass by 70.2% (±25.7), total soil C content by 21.4% (±1.7), and soil organic carbon (SOC) concentration by 14.3% (±0.8), on average, as compared to moderate‐to‐heavy (MtH) grazing. Plant biotypes responded to grazing activities differently; alpine meadows increased total soil C content by 107.2%, alpine steppes increased SOC by 52.2%, but desert steppes decreased total C content by 21.8% under the grazing exclusion. All plant biotypes reduced soil bulk density by 6.4%–19.4% under grazing exclusion. Soil microbial community diversity responded to grazing activities inconsistently, ranging from an 18% decrease to a 26% increase in soil microbial diversity compared to MtH grazing. We conclude that selecting appropriate plant biotypes alongside improved grazing management will enhance grassland ecosystem functions and services as plant biotypes affect aboveground and belowground biomass and interface with soil physiochemical properties.
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- 2023
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9. Laboratory Assessment of Modified Asphalt Binders Using Crumb Rubber Modifier (CRM) and Processed Oil
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Navid Hemmati, Shyaamkrishnan Vigneswaran, Mithil Mazumder, Moon-Sup Lee, and Soon-Jae Lee
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CRM ,processed oil ,viscosity ,rutting ,stiffness ,workability ,Building construction ,TH1-9745 - Abstract
The study examines the effects of modifying PG 64-22 asphalt binder with Crumb Rubber Modifier (CRM) and processed oil on its properties. The binder was tested at different temperatures, and different amounts of CRM and processed oil were added to the binder. The modified binders were also aged using different procedures. The study found that adding processed oil to CRM-modified binders reduces viscosity and improves workability, while CRM improves the rutting resistance. However, the addition of processed oil reduces the binder’s rutting performance. The study also found that CRM and processed oil improve the low temperature cracking resistance. The study’s results indicate that co-modifying CRM binders with processed oil resulted in a significant reduction in viscosity values, resulting in improved workability. The results also showed that increasing the processed oil concentration from 6% to 12% caused a viscosity reduction of 27%, 34%, 33%, and 31% for modified binders containing 0, 5%, 10%, and 15% CRM, respectively. Even though the addition of processed oil results in a reduction in the rutting performance of asphalt binder, the addition of CRM significantly improved the rutting resistance of asphalt binders. The CRM binder containing processed oil decreased the G*sin δ values, and the content of 6% processed oil containing 5%, 10%, and 15% CRM decreased by 28%, 17%, and 11%, respectively, while the 12% processed oil-modified asphalt binder showed a reduction in G*sin δ by 5%, 13%, and 22%, respectively. The BBR results for modified asphalt binders showed that the incorporation of CRM and processed oil improved the low temperature cracking resistance significantly. The stiffness values with 6% processed oil containing 5%, 10%, and 15% CRM were observed to be 118, 97, and 80 MPa, respectively, while at the same temperature for the same CRM contents with 12% processed oil, the stiffness values were found to be 89, 72, and 56 MPa, respectively.
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- 2023
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10. Using enzyme activities as an indicator of soil fertility in grassland - an academic dilemma
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Li Wang, Chantal Hamel, Peina Lu, Junying Wang, Dandi Sun, Yijia Wang, Soon-Jae Lee, and Gary Y. Gan
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ecosystem functions and services ,ecosystem sustainability and resilience ,microbial biomass ,soil biochemical property ,physiochemical property ,Plant culture ,SB1-1110 - Abstract
Grasslands play an important role in conserving natural biodiversity and providing ecosystem functions and services for societies. Soil fertility is an important property in grassland, and the monitoring of soil fertility can provide crucial information to optimize ecosystem productivity and sustainability. Testing various soil physiochemical properties related to fertility usually relies on traditional measures, such as destructive sampling, pre-test treatments, labor-intensive procedures, and costly laboratory measurements, which are often difficult to perform. However, soil enzyme activity reflecting the intensity of soil biochemical reactions is a reliable indicator of soil properties and thus enzyme assays could be an efficient alternative to evaluate soil fertility. Here, we review the latest research on the features and functions of enzymes catalyzing the biochemical processes that convert organic materials to available plant nutrients, increase soil carbon and nutrient cycling, and enhance microbial activities to improve soil fertility. We focus on the complex relationships among soil enzyme activities and functions, microbial biomass, physiochemical properties, and soil/crop management practices. We highlight the biochemistry of enzymes and the rationale for using enzyme activities to indicate soil fertility. Finally, we discuss the limits and disadvantages of the potential new molecular tool and provide suggestions to improve the reliability and feasibility of the proposed alternative.
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- 2023
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11. A metabarcoding protocol targeting two DNA regions to analyze root‐associated fungal communities in ferns and lycophytes
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Thais Guillen‐Otero, Soon‐Jae Lee, Cheng‐Wei Chen, Peter Szoevenyi, and Michael Kessler
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amplicons ,DNA sequencing ,ferns ,ITS ,metabarcoding ,mycorrhizal fungi ,Biology (General) ,QH301-705.5 ,Botany ,QK1-989 - Abstract
Abstract Premise Detailed studies of the fungi associated with lycophytes and ferns provide crucial insights into the early evolution of land plants. However, most investigations to date have assessed fern–fungus interactions based only on visual root inspection. In the present research, we establish and evaluate a metabarcoding protocol to analyze the fungal communities associated with fern and lycophyte roots. Methods We used two primer pairs focused on the ITS rRNA region to screen the general fungal communities, and the 18S rRNA to target Glomeromycota fungi (i.e., arbuscular mycorrhizal fungi). To test these approaches, we collected and processed roots from 12 phylogenetically distant fern and lycophyte species. Results We found marked compositional differences between the ITS and 18S data sets. While the ITS data set demonstrated the dominance of orders Glomerales (phylum Glomeromycota), Pleosporales, and Helotiales (both in phylum Ascomycota), the 18S data set revealed the greatest diversity of Glomeromycota. Non‐metric multidimensional scaling (NMDS) ordination suggested an important geographical effect in sample similarities. Discussion The ITS‐based approach is a reliable and effective method to analyze the fungal communities associated with fern and lycophyte roots. The 18S approach is more appropriate for studies focused on the detailed screening of arbuscular mycorrhizal fungi.
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- 2023
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12. Draft Genome of Nocardia canadensis sp. nov. Isolated from Petroleum-Hydrocarbon-Contaminated Soil
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Fahad Alotaibi, Soon-Jae Lee, Zakaria Lahrach, Marc St-Arnaud, and Mohamed Hijri
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alkane 1-monooxygenase (alkB) ,alkanes ,genome sequencing ,Nocardia canadensis ,plant-growth-promoting rhizobacteria ,Biology (General) ,QH301-705.5 - Abstract
The bacterial strain WB46 was isolated from the rhizosphere of willow plants (Salix purpurea L.) growing in soil contaminated with petroleum hydrocarbons. The strain was subjected to whole-genome shotgun sequencing using Illumina HiSeq. Its draft genome is 7.15 Mb, with a 69.55% GC content, containing 6387 protein-coding genes and 51 tRNA and 15 rRNA sequences. The quality and reliability of the genome were assessed using CheckM, attaining an estimated genome completeness of 98.75% and an estimated contamination of 1.68%. These results indicate a high-quality genome (>95%) and low contamination (alkB) and naphthalene dioxygenase (ndo). 16S rRNA gene analysis, including in silico DNA–DNA hybridization (DDH) and average nucleotide identity (ANI), showed that strain WB46 belongs to the genus Nocardia, and the most closely related species is Nocardia asteroides. The strain WB46 showed a distance of 63.4% and sequence identity of 88.63%, respectively. These values fall below the threshold levels of 70% and 95%, respectively, suggesting that the strain WB46 is a new species. We propose the name of Nocardia canadensis sp. nov. for this new species. Interestingly, the sequence divergence of the 16S rRNA gene showed that the divergence only occurred in the V2 region. Therefore, the conventional V3–V4, V5–V7, or V8–V9 targeting metabarcoding, among others, would not be able to assess the diversity related to this new species.
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- 2023
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13. Biochar Improved Sugarcane Growth and Physiology under Salinity Stress
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Ngoc-Thang Vu, The-Khuynh Bui, Thi-Thuy-Hang Vu, Thu-Huyen Nguyen, Thi-Tuyet-Cham Le, Anh-Tuan Tran, Ngoc-Lan Vu, Van-Quang Tran, Van-Giang Tong, Xuan-Truong Nguyen, Hwi-Chan Yang, Soon-Jae Lee, Young-Ho Kim, Yun-Hyeong Bae, Soon-Jae Hyeon, Thai-Hoang Dinh, and Dong-Cheol Jang
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biochar ,growth ,physiology ,saline ,sugarcane ,Technology ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Biology (General) ,QH301-705.5 ,Physics ,QC1-999 ,Chemistry ,QD1-999 - Abstract
Biochar is suggested as a conditioner for salt-affected soils for various crops. This study aimed to evaluate the effects of biochar on the growth and physiology of sugarcane under saline and non-saline conditions at an early growth stage. The experiment was conducted in pots in the greenhouses with three replications. Three biochar rates (0, 5, and 10 tons ha−1) were applied before transplanting sugarcane seedlings into the pots. Four weeks after transplanting, plants were irrigated with 300 mL of 100 mM NaCl every two days for 2 weeks. Salinity significantly affected the growth and physiology of sugarcanes. The application of biochar increased plant height, shoot dry weight, root volume, root dry weight, Fv/Fm, and chlorophyll content while decreasing the water saturation deficit and the relative ion leakage in the leaves under both saline and non-saline conditions. Thus, biochar application has positive effects on the growth and physiology of sugarcane at an early growth stage under both saline and non-saline conditions. However, further study is suggested to investigate the effects of biochar on sugarcane under saline stress in the field at different growth stages.
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- 2023
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14. Effect of Kaolinite and Cloisite Na+ on Storage Stability of Rubberized Binders
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Shyaamkrishnan Vigneswaran, Jihyeon Yun, Moon-Sup Lee, and Soon-Jae Lee
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Superpave test ,multiple shear creep recovery ,high temperature ,crumb rubber modifier ,nanocomposite clay ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
This study aimed to evaluate the impact of a two-step modification process involving kaolinite and cloisite Na+ on the storage stability of rubberized binders. The process involved the manual combination of virgin binder PG 64-22 with crumb rubber modifier (CRM), which was heated to condition it. The preconditioned rubberized binder was then modified for two hours at a high speed of 8000 rpm using wet mixing. The second stage modification was performed in two parts, with part 1 using only crumb rubber as the modifier and part 2 involving the use of kaolinite and montmorillonite nano clays at a replacement percentage of 3% to the original weight of the binder along with the crumb rubber modifier. The Superpave and multiple shear creep recovery (MSCR) test methods were used to calculate the performance characteristics and separation index % of each modified binder. The results showed that the viscosity properties of kaolinite and montmorillonite improved the performance class of the binder, with montmorillonite demonstrating greater viscosity values than kaolinite even at high temperatures. Additionally, kaolinite with rubberized binders showed higher resistance to rutting, and the % recovery value from multiple shear creep recovery testing indicated that kaolinite with rubberized binders was more effective than montmorillonite with rubberized binders, even at higher load cycles. The use of kaolinite and montmorillonite reduced phase separation between the asphaltene phase and rubber-rich phase at higher temperatures, but the performance of the rubber binder was affected by higher temperatures. Overall, kaolinite with the rubber binder generally demonstrated greater binder performance.
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- 2023
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15. Effect of Blending and Curing Conditions on the Storage Stability of Rubberized Asphalt Binders
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Jihyeon Yun, Shyaamkrishnan Vigneswaran, Moon-Sup Lee, Pangil Choi, and Soon-Jae Lee
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CRM binder ,storage stability ,separation index ,viscosity ,G*/sin δ ,percentage recovery ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
Crumb rubber modifier (CRM) binders easily suffer from instability at high temperatures, with many suggestions being developed to evaluate their storage stability. However, much uncertainty around CRM binders still exists regarding the relationship between mixing methods and experiments in order to calculate the separation index. In this study, a laboratory investigation into how CRM binders behave regarding storage stability using different mixing methods and experiments was conducted. The CRM asphalt binder in this study was prepared through a wet mixing process with the addition of 5% and 10% crumb rubber modifier (by weight) at 200 °C. The three main modification methods were method A: high-shear mixing (8000 rpm) for 2 h, method B: low mixing (300 rpm) for 8 h, and method C: high-shear mixing (8000 rpm) for 2 h + low mixing (300 rpm) for 6 h. In addition, the effect of separation index (SI) on storage stability was assessed, measuring viscosity, G*/sin δ, and percentage recovery. In general, the results of this study revealed that method C appeared to have the most prominent effect on decreasing the difference between the values of the top and bottom parts; the results for 5% CRM using method C showed that there were no differences among the values for the top, middle, and bottom parts; from the MSCR test, method C was effective in decreasing the difference between the values of the top and bottom parts. It was observed that method C improved storage stability. However, the results for percentage recovery were relatively higher than the separation index when using rotational viscosity and G*/sin δ.
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- 2023
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16. Laboratory Evaluation of Asphalt Binders Containing Styrene-Butadiene-Styrene (SBS) and Processed Oil
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Navid Hemmati, Shyaamkrishnan Vigneswaran, Hyun Hwan Kim, Moon-Sup Lee, and Soon-Jae Lee
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processed oil ,SBS ,viscosity ,stiffness ,Technology ,Electrical engineering. Electronics. Nuclear engineering ,TK1-9971 ,Engineering (General). Civil engineering (General) ,TA1-2040 ,Microscopy ,QH201-278.5 ,Descriptive and experimental mechanics ,QC120-168.85 - Abstract
The study presents an experimental evaluation to improve the resistivity of binders with “Styrene-Butadiene-Styrene” (SBS) and “Processed oil” by studying the physical properties, rheology, and cracking. For this experiment, PG 64-22 was mixed with SBS at different percentages of 5%, 10%, and 15% by weight of the original binder with two processed oil contents of 6% and 12% by weight of the binder. Laboratory tests have been conducted at various high, medium, and low temperature ranges to evaluate their properties. The processed oil polymer modified asphalt (PMA) binder is artificially aged in both the short and long-term using a Rolling Thin Film Oven (RTFO) and a Pressure Aging Vessel (PAV). The Superpave testing method was performed on modified binders using a Rotational Viscometer (RV), Dynamic Shear Rheometer (DSR), and Bending Beam Rheometer (BBR). The results of this study illustrate (1) The addition of SBS leads to higher viscosity, but the co-modification of asphalt binder with the processed oil shows a significant modulation of the viscosity value. (2) In addition, processed oil reduced the resistance to rutting, but the addition of SBS significantly improved the rutting resistance of the asphalt binder. (3) The addition of SBS and processed oil improved the value of G sin δ, notably. (4) According to BBR, it has been shown that the addition of SBS in addition to the processed oil improves the stiffness values of modified asphalt binders.
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- 2023
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17. Spin angular momentum-encoded single-photon emitters in a chiral nanoparticle-coupled WSe 2 monolayer.
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Soon-Jae Lee, Jae-Pil So, Ryeong Myeong Kim, Kyoung-Ho Kim, Hyun-Ho Rha, Gunwoo Na, Jeong Hyun Han, Kwang-Yong Jeong, Ki Tae Nam, and Hong-Gyu Park
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- *
QUANTUM optics , *CIRCULAR polarization , *STOKES parameters , *GOLD nanoparticles , *QUANTUM cryptography - Abstract
Spin angular momentum (SAM)-encoded single-photon emitters, also known as circularly polarized single photons, are basic building blocks for the advancement of chiral quantum optics and cryptography. Despite substantial efforts such as coupling quantum emitters to grating-like optical metasurfaces and applying intense magnetic fields, it remains challenging to generate circularly polarized single photons from a subwavelength-scale nanostructure in the absence of a magnetic field. Here, we demonstrate single-photon emitters encoded with SAM in a strained WSe2 monolayer coupled with chiral plasmonic gold nanoparticles. Single-photon emissions were observed at the nanoparticle position, exhibiting photon antibunching behavior with a g(2)(0) value of ~0.3 and circular polarization properties with a slight preference for left-circular polarization. Specifically, the measured Stokes parameters confirmed strong circular polarization characteristics, in contrast to emitters coupled with achiral gold nanocubes. Therefore, this work provides potential insights to make SAM-encoded single-photon emitters and understand the interaction of plasmonic dipoles and single photons, facilitating the development of chiral quantum optics. [ABSTRACT FROM AUTHOR]
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- 2024
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18. Welding Properties of Dissimilar Al-Cu Thin Plate by a Single-Mode Fiber Laser
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Soon-Jae Lee, Kwang-Deok Choi, Su-Jin Lee, Dong-Sik Shin, and Jae-Pil Jung
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laser welding ,dissimilar welding ,single-mode laser ,aluminum ,copper ,Mining engineering. Metallurgy ,TN1-997 - Abstract
To improve the reliability and safety of the electrical components used in automobiles, Cu and Al have recently been employed as electrodes, wherein lasers were used for rapid welding. However, in Al-Cu dissimilar metal welding, intermetallic compounds (IMCs) reduce the weld strength. In addition, the laser absorption rates of Al and Cu are low, and the reflectance is high, thereby impeding the welding process. To increase the absorption rate, a laser with a high beam quality must be used. Thus, a high-density, high-quality 5 kW single-mode laser was employed. Thin Al and Cu (0.2 mm thick) plates were processed and welded at welding speed 200–1000 mm/s, changing the laser-irradiated upper metal to Cu or Al. Post analysis, it was found that with a high heat input, pores were generated inside the Al, and when the upper metal was Cu, pores were mainly generated between the Al molten layer and the Cu mixed layer. As a result of tensile shear strength measurement, most of the aluminum area fractured at 118–151 N, and when fractured in copper, the strength was highest at 154 N. At a high welding speed, fracture was mainly observed at the joints along the IMCs or in the Cu mixed layer.
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- 2022
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19. Optical Characterization of Asphalt Binders Containing Wax Additives
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Mithil Mazumder, Raju Ahmed, Moon-Sup Lee, and Soon-Jae Lee
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Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
In between thermal-oxidative (heat and oxygen) and photo-oxidative (ultraviolet irradiation and oxygen) aging process of bitumen, photo-oxidative aging mainly depends on the optical properties of the asphalt binder. The higher the reflection (or the lower the absorption of the binders), the better the pavement serviceability. The literature review indicates that there is limited research conducted on the optical properties of the binder with wax additives. In this paper, the optical properties of commonly used binders (PG 64-22, Rubber modified binder, and SBS modified binder) containing wax additives (LEADCAP and Sasobit) were investigated using UV-Vis spectrometer. The result of this study showed that (1) the addition of modifiers (crumb rubber and SBS) with the base binder slightly increases the absorption of the binder; (2) the binder types and aging level have significant contribution on optical properties; (3) in general, the aged binders were observed to have higher reflectivity compared to the unaged binders; and (4) the addition of wax additives is observed to have a significant effect on the optical properties.
- Published
- 2020
- Full Text
- View/download PDF
20. Laboratory Evaluation of SBS Modified Asphalt Binder Containing GTR, SIS, and PE
- Author
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Hyun Hwan Kim, Mithil Mazumder, Moon-Sup Lee, and Soon-Jae Lee
- Subjects
Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
Performance properties of polymer modified asphalt (PMA) binders with Styrene-isoprene-styrene (SIS), petroleum resin (PE), and ground tire rubber (GTR) were evaluated at high, intermediate, and low temperatures. Styrene-butadiene-styrene (SBS) PMA binder of PG 76-22 was used as a base binder. The PG76 SBS PMA binders were blended with SIS, PE, and three different GTR contents (0, 5, and 10%). The binders were artificially short-term and long-term aged using rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were conducted on the binders through rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR). Multiple stress creep recovery (MSCR) test was also performed to evaluate the rutting property. The results of this study indicated that (1) the addition of PE can decrease the binder viscosity, (2) although the incorporation of GTR and SIS significantly improve the rutting resistance of the binders, the effect of PE is found to be insignificant, (3) PE is observed to have positive effect on the cracking properties of control PG76 SBS PMA binder blended with SIS and GTR, and (4) incorporation of PE might be an useful option to improve the workability of high performance PMA binder in lieu with maintaining good rutting and cracking resistance.
- Published
- 2020
- Full Text
- View/download PDF
21. Rheological and Morphological Characterization of Styrene-Isoprene-Styrene (SIS) Modified Asphalt Binder
- Author
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Mithil Mazumder, Anwar Siddique, Raju Ahmed, Soon-Jae Lee, and Moon-Sup Lee
- Subjects
Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
The demand of strong polymer modified asphalt (PMA) binder is growing due to the increase of traffic and necessity to reduce the early deterioration of pavement due to cracking. In this study, physical and rheological properties of asphalt binder modified with a potential new polymer named styrene-isoprene-styrene (SIS) were investigated through the rotational viscometer (RV), the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). In order to have a depth understanding on the SIS binder at micro level, micro-morphological observations were conducted using optical microscopy, atomic force microscopy (AFM), environmental scanning electron microscopy (ESEM), and ellipsometry. The result of this study showed that (1) the addition of SIS modifiers increased the viscosity and had a positive effect on rutting resistance of the binder; (2) the addition of 5%, 10%, 15%, and 20% SIS content increased the rutting resistance by 600%, 3000%, 5600%, and 6400%, respectively; (3) the higher the SIS content, the better the cracking resistance of the binder and it is observed to have improved the stiffness by 26% and 51% with the addition of 5% and 10% content of SIS, respectively; (4) AFM images showed the significant correlation between the stiffness and microstructural properties of the binder; (5) the dominance of new oval phase over network structure was evident in ESEM images and observed to have significant correlation to the high stiffness of the binder; and (6) with the percentage increase of SIS modifier, the binder is found to have higher absorption at UV wavelength.
- Published
- 2020
- Full Text
- View/download PDF
22. Biochar Improved Sugarcane Growth and Physiology under Salinity Stress
- Author
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Jang, Ngoc-Thang Vu, The-Khuynh Bui, Thi-Thuy-Hang Vu, Thu-Huyen Nguyen, Thi-Tuyet-Cham Le, Anh-Tuan Tran, Ngoc-Lan Vu, Van-Quang Tran, Van-Giang Tong, Xuan-Truong Nguyen, Hwi-Chan Yang, Soon-Jae Lee, Young-Ho Kim, Yun-Hyeong Bae, Soon-Jae Hyeon, Thai-Hoang Dinh, and Dong-Cheol
- Subjects
biochar ,growth ,physiology ,saline ,sugarcane - Abstract
Biochar is suggested as a conditioner for salt-affected soils for various crops. This study aimed to evaluate the effects of biochar on the growth and physiology of sugarcane under saline and non-saline conditions at an early growth stage. The experiment was conducted in pots in the greenhouses with three replications. Three biochar rates (0, 5, and 10 tons ha−1) were applied before transplanting sugarcane seedlings into the pots. Four weeks after transplanting, plants were irrigated with 300 mL of 100 mM NaCl every two days for 2 weeks. Salinity significantly affected the growth and physiology of sugarcanes. The application of biochar increased plant height, shoot dry weight, root volume, root dry weight, Fv/Fm, and chlorophyll content while decreasing the water saturation deficit and the relative ion leakage in the leaves under both saline and non-saline conditions. Thus, biochar application has positive effects on the growth and physiology of sugarcane at an early growth stage under both saline and non-saline conditions. However, further study is suggested to investigate the effects of biochar on sugarcane under saline stress in the field at different growth stages.
- Published
- 2023
- Full Text
- View/download PDF
23. Evaluation of High-Performance Asphalt Binders Modified with SBS, SIS, and GTR
- Author
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Hyun Hwan Kim, Mithil Mazumder, Moon-Sup Lee, and Soon-Jae Lee
- Subjects
Engineering (General). Civil engineering (General) ,TA1-2040 - Abstract
In this study, performance properties of polymer-modified asphalt (PMA) binders are evaluated depending on ground tire rubber (GTR) and styrene-isoprene-styrene (SIS). Styrene-butadiene-styrene- (SBS-) modified asphalt binder of PG 76-22 is used as a base binder to manufacture the rubberized PMA binder. The rubberized PMA binders are blended using SIS modifier. The binders were artificially short-term and long-term aged using rolling thin-film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were conducted on the binders through rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR). Furthermore, multiple stress creep recovery (MSCR) test and atomic force microscopy (AFM) microstructural analysis were performed. The results of this study indicated that (1) the viscosity properties seem to be highly dependent on GTR and SIS contents, (2) the addition of SIS is observed to have a significant effect on improving the rutting performances of rubberized PMA binders, (3) the cracking properties are considered to be improved significantly through SIS modification, and (4) in general, the rubberized PMA binders with SIS showed the best performance for rutting and cracking among all the binders used in this study.
- Published
- 2019
- Full Text
- View/download PDF
24. The paradox of feminism and beautification of outward appearance
- Author
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Eun Su Jang and Soon Jae Lee
- Published
- 2021
25. A study on social responsibility of beauty design
- Author
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You Kyoung Park and Soon Jae Lee
- Published
- 2021
26. Investigation of Rheological Properties of Blended Cement Pastes Using Rotational Viscometer and Dynamic Shear Rheometer
- Author
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Yoo Jae Kim, Bum-Yean Cho, Soon-Jae Lee, Jiong Hu, and James W. Wilde
- Subjects
Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
To successfully process concrete, it is necessary to predict and control its flow behavior. However, the workability of concrete is not completely measured or specified by current standard tests. Furthermore, it is only with a clear picture of cement hydration and setting that full prediction and control of concrete performance can be generalized. In order to investigate the rheological properties of blended cement pastes, a rotational viscometer (RV) was used to determine the flow characteristics of ordinary and blended pastes to provide assurance that it can be pumped and handled. Additionally, a dynamic shear rheometer (DSR) was used to characterize both the viscous and elastic components of pastes. Ordinary Portland cement paste and blended pastes (slag, fly ash, and silica fume) were investigated in this study. The stress and strain of the blended specimens were measured by the DSR, which characterizes both viscous and elastic behaviors by measuring the complex shear modulus (the ratio of total shear stress to total shear strain) and phase angle (an indicator of the relative amounts of recoverable and nonrecoverable deformation) of materials. Cement pastes generally exhibit different rheological behaviors with respect to age, mineral admixture type, and cement replacement level.
- Published
- 2018
- Full Text
- View/download PDF
27. Generation of unequal nuclear genotype proportions in Rhizophagus irregularis progeny causes allelic imbalance in gene transcription
- Author
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Ian R. Sanders, Consolée Aletti, Joaquim Cruz Corella, Ivan D. Mateus, Chanz Robbins, Soon-Jae Lee, Frédéric G Masclaux, and Réjane Seiler
- Subjects
Rhizophagus irregularis ,Genotype ,Physiology ,AMF genetics ,Plant Science ,Allelic Imbalance ,plant symbiosis ,Mycorrhizae ,Genetic variation ,Allele ,Glomeromycota ,Symbiosis ,Gene ,Allele frequency ,Ecosystem ,Dikaryon ,2. Zero hunger ,Genetics ,Full Paper ,biology ,arbuscular mycorrhiza ,Research ,fungi ,Fungi ,Full Papers ,15. Life on land ,biology.organism_classification ,plant production ,Transcriptome - Abstract
Summary Arbuscular mycorrhizal fungi (AMF) form mutualisms with most plant species. The model AMF Rhizophagus irregularis is common in many ecosystems and naturally forms homokaryons and dikaryons. Quantitative variation in allele frequencies in clonally dikaryon offspring suggests they disproportionately inherit two distinct nuclear genotypes from their parent. This is interesting, because such progeny strongly and differentially affect plant growth. Neither the frequency and magnitude of this occurrence nor its effect on gene transcription are known.Using reduced representation genome sequencing, transcriptomics, and quantitative analysis tools, we show that progeny of homokaryons and dikaryons are qualitatively genetically identical to the parent. However, dikaryon progeny differ quantitatively due to unequal inheritance of nuclear genotypes. Allele frequencies of actively transcribed biallelic genes resembled the frequencies of the two nuclear genotypes.More biallelic genes showed transcription of both alleles than monoallelic transcription, but biallelic transcription was less likely with greater allelic divergence. Monoallelic transcription levels of biallelic genes were reduced compared with biallelic gene transcription, a finding consistent with genomic conflict.Given that genetic variation in R. irregularis is associated with plant growth, our results establish quantitative genetic variation as a future consideration when selecting AMF lines to improve plant production.
- Published
- 2021
28. Laboratory Assessment of Asphalt Binders Containing Petroleum Resin
- Author
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Mithil Mazumder, Moon-Sup Lee, Navid Hemmati, Hyun Hwan Kim, and Soon-Jae Lee
- Subjects
050210 logistics & transportation ,Materials science ,Rut ,Rheometer ,05 social sciences ,0211 other engineering and technologies ,02 engineering and technology ,Viscosity ,Cracking ,chemistry.chemical_compound ,Rheology ,chemistry ,Mechanics of Materials ,Asphalt ,Petroleum resin ,021105 building & construction ,0502 economics and business ,Dynamic shear rheometer ,Composite material ,Civil and Structural Engineering - Abstract
Asphalt is one of the most common materials in the pavement industry and faces thermal cracks, fatigue cracks, and rutting mechanical defects due to its temperature-dependent behavior. Polymer-modified asphalt (PMA) binders are being considered to reduce the impact of the mentioned. This study reports the laboratory assessment of asphalt binder containing petroleum resin (PE). PG 64-22 was used as a base binder and modified with PE modifiers at different content (0, 5, 10, 15 and 20%, by the weight of the binder). The PE-modified binders were artificially short-term and long-term aged using rolling thin film oven (RTFO) and pressure aging vessel (PAV), respectively. The physical and rheological properties of the binders were evaluated using rotational viscometer (RV), dynamic shear rheometer (DSR) and bending beam rheometer (BBR). Furthermore, multiple stress recovery (MSCR) test was performed to investigate the percent recovery of the PE-modified binder. The results of this study indicated that (1) the addition of PE modifier increases the binder viscosity, (2) PE modifier has the potential to improve the rutting resistance of the binders, (3) PE modifier is observed to have increased the %rec of the binders, and (4) PE modifier is found to have negative effect on the fatigue and low-temperature cracking resistance of the binders.
- Published
- 2021
29. The characteristics of modern Chinese menswear design
- Author
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Soon Jae Lee and Wei Pan
- Published
- 2021
30. Laboratory Evaluation of Storage Stability for CRM Asphalt Binders
- Author
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Jihyeon Yun, Navid Hemmati, Moon-Sup Lee, and Soon-Jae Lee
- Subjects
Renewable Energy, Sustainability and the Environment ,Geography, Planning and Development ,CRM binder ,storage stability ,separation index ,viscosity ,G*/sin δ ,Building and Construction ,Management, Monitoring, Policy and Law - Abstract
This paper conveys the laboratory investigation of the storage stability of CRM binder as a basic study. The CRM binder was produced through the wet process in the laboratory. The percentages of crumb rubber used for rubberized binder were 5%, 10%, 15% and 20%. The samples were prepared according to ASTM D7173. In order to evaluate the properties of each part of the binders, tests were carried out through the rotational viscosity and viscoelasticity, and the separation index was assessed with the G*/sin δ and %rec. In general, the results of this study revealed that (1) the conditioned CRM binders appeared to have higher viscosity in the bottom part compared to the middle and top parts.; (2) similar to the viscosity results, the CRM binders after conditioning showed the highest G*/sin δ value in the bottom part; (3) from the MSCR test, Jnr and % rec values are observed to have a similar trend with G*/sin δ results, although some of the data were not measured due to the higher load than the DSR test; and (4) it was discovered that the SI from G*/sin δ generally used was suitable for evaluating the storage stability of CRM asphalt binders, compared to the SI from % rec.
- Published
- 2022
- Full Text
- View/download PDF
31. Reciprocal recombination genomic signatures in the symbiotic arbuscular mycorrhizal fungi Rhizophagus irregularis
- Author
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Ivan D. Mateus, Ben Auxier, Mam M. S. Ndiaye, Joaquim Cruz, Soon-Jae Lee, and Ian R. Sanders
- Subjects
Recombination, Genetic ,Multidisciplinary ,Mycorrhizae ,Fungi ,Life Science ,Laboratory of Genetics ,Genomics ,Genome, Fungal ,Plants ,Symbiosis ,PE&RC ,Laboratorium voor Erfelijkheidsleer - Abstract
Arbuscular mycorrhizal fungi (AMF) are part of the most widespread fungal-plant symbiosis. They colonize at least 80% of plant species, promote plant growth and plant diversity. These fungi are multinucleated and contain either one or two haploid nuclear genotypes (monokaryon and dikaryon) identified by the alleles at a putative mating-type locus. This taxon has been considered as an ancient asexual scandal because of the lack of observable sexual structures. Despite identification of a putative mating-type locus and functional activation of genes related to mating when two isolates co-exist, it remains unknown if the AMF life cycle involves a sexual or parasexual stage. We used publicly available genome sequences to test if Rhizophagus irregularis dikaryon genomes display signatures of sexual reproduction in the form of reciprocal recombination patterns, or if they display exclusively signatures of parasexual reproduction involving gene conversion. We used short-read and long-read sequence data to identify nucleus-specific alleles within dikaryons and then compared them to orthologous gene sequences from related monokaryon isolates displaying the same putative MAT-types as the dikaryon. We observed that the two nucleus-specific alleles of the dikaryon A5 are more related to the homolog sequences of monokaryon isolates displaying the same putative MAT-type than between each other. We also observed that these nucleus-specific alleles displayed reciprocal recombination signatures. These results confirm that dikaryon and monokaryon isolates displaying the same putative MAT-type are related in their life-cycle. These results suggest that a genetic exchange mechanism, involving reciprocal recombination in dikaryon genomes, allows AMF to generate genetic diversity.
- Published
- 2022
32. Assessing the warm glow effect in contingent valuations for public libraries.
- Author
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Soon-Jae Lee, Hye-Kyung Chung, and Eun-Joo Jung
- Published
- 2010
- Full Text
- View/download PDF
33. Co-existence of AMF with different putative MAT-alleles induces genes homologous to those involved in mating in other fungi: a reply to Malar et al
- Author
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Ian R. Sanders, Ivan D. Mateus, and Soon-Jae Lee
- Subjects
Genetics ,Reproduction ,Comment ,Fungi ,Alleles ,Fungi/genetics ,Genes, Fungal ,Biology ,Microbiology ,Plant Roots ,Microbial ecology ,Mycorrhizae ,Homologous chromosome ,Allele ,Mating ,Fungal ecology ,Glomeromycota ,Symbiosis ,Gene ,Ecology, Evolution, Behavior and Systematics - Abstract
Arbuscular mycorrhizal fungi (AMF) are of great ecological importance because of their effects on plant growth. Closely related genotypes of the same AMF species coexist in plant roots. However, almost nothing is known about the molecular interactions occurring during such coexistence. We compared in planta AMF gene transcription in single and coinoculation treatments with two genetically different isolates of Rhizophagus irregularis in symbiosis independently on three genetically different cassava genotypes. Remarkably few genes were specifically upregulated when the two fungi coexisted. Strikingly, almost all of the genes with an identifiable putative function were known to be involved in mating in other fungal species. Several genes were consistent across host plant genotypes but more upregulated genes involved in putative mating were observed in host genotype (COL2215) compared with the two other host genotypes. The AMF genes that we observed to be specifically upregulated during coexistence were either involved in the mating pheromone response, in meiosis, sexual sporulation or were homologs of MAT-locus genes known in other fungal species. We did not observe the upregulation of the expected homeodomain genes contained in a putative AMF MAT-locus, but observed upregulation of HMG-box genes similar to those known to be involved in mating in Mucoromycotina species. Finally, we demonstrated that coexistence between the two fungal genotypes in the coinoculation treatments explained the number of putative mating response genes activated in the different plant host genotypes. This study demonstrates experimentally the activation of genes involved in a putative mating response and represents an important step towards the understanding of coexistence and sexual reproduction in these important plant symbionts.
- Published
- 2021
34. Cost effectiveness of crack treatment methods: A field study
- Author
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Moon-Sup Lee, Soon-Jae Lee, Hyun Hwan Kim, and Mithil Mazumder
- Subjects
050210 logistics & transportation ,Cost effectiveness ,business.industry ,Sealant ,05 social sciences ,lcsh:TA1001-1280 ,0211 other engineering and technologies ,Treatment method ,Transportation ,02 engineering and technology ,Structural engineering ,Asphalt ,Initial cost ,Long period ,021105 building & construction ,0502 economics and business ,Life cycle costs ,Environmental science ,lcsh:Transportation engineering ,business ,Civil and Structural Engineering ,Cost database - Abstract
In the United States, more than 94% highways are paved with asphalt materials and placing crack sealant materials has been a common pavement maintenance for decades. Crack sealing treatment includes the use of a router to create a reservoir on the intended cracks whereas crack filling is given without doing any modification to the crack wall. Although the initial cost of crack sealing is higher, it is expected to have a longer service period compared to crack filling. There is little research on comparison of short and long term cost effectiveness between these two treatments using the real field cost data analysis. In this study four test sites in Texas were treated with crack filling and sealing using the same sealant material and finishing technique. Cost effectiveness of both treatments was measured in terms of initial, annual average and life cycle cost based on the cost inputs during construction. In general, the results of this study indicated that (1) on an average approximately 45% initial cost increase was estimated with the two routing configurations of crack sealing; (2) material and labor cost is found to have the most significant effect on the higher initial cost of crack sealing compared to other associated costs; (3) annual average and life cycle costs have shown that crack sealing is more cost effective pavement maintenance compared to crack filling over a long period of time; (4) agency cost is observed to be reduced by approximately 24% with crack sealing treatment based on the 35 year analysis period. Keywords: Crack sealing, Crack filling, Initial cost, Annual average cost, Life cycle cost
- Published
- 2019
35. Effect of production process on performance properties of warm rubberized binders
- Author
-
Hyun Hwan Kim, Mithil Mazumder, Moon-Sup Lee, and Soon-Jae Lee
- Subjects
050210 logistics & transportation ,Wax ,Materials science ,Fatigue cracking ,Rut ,Rheometer ,05 social sciences ,lcsh:TA1001-1280 ,0211 other engineering and technologies ,Transportation ,02 engineering and technology ,Rotational viscometer ,Bending beam ,Viscosity ,visual_art ,021105 building & construction ,0502 economics and business ,Dynamic shear rheometer ,visual_art.visual_art_medium ,lcsh:Transportation engineering ,Composite material ,Civil and Structural Engineering - Abstract
The study presents an experimental evaluation of performance properties of two different production processes of warm rubberized binder. Two types of rubberized binder were produced through dry process and wet process and two of the available wax additives were added into the rubberized binders (i.e., LEADCAP and Sasobit). Rubberized binders with wax additives were artificially short-term and long-term aged using the rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were carried out on the binders through the rotational viscometer (RV), the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). In general, the results of this study indicated that (1) the viscosity properties have been found to be similar between dry and wet processes, (2) the rubberized binders manufactured by wet process were observed to have the higher rutting resistance than those by dry process, (3) the wet process resulted in better performance in the fatigue cracking test than the dry process, and (4) the blending method was found to have little influence of stiffness properties. Keywords: Rubberized binder, Dry process, Wet process, Viscosity, Rutting, Fatigue cracking
- Published
- 2019
36. Spectroscopic Ellipsometry of Asphalt Binder: A Study of Optical Constants
- Author
-
Mehedhi Hasan, Soon-Jae Lee, Raju Ahmed, Moon-Sup Lee, and Mithil Mazumder
- Subjects
Materials science ,0211 other engineering and technologies ,Analytical chemistry ,02 engineering and technology ,Molar absorptivity ,021001 nanoscience & nanotechnology ,Spectral line ,Wavelength ,Attenuation coefficient ,021105 building & construction ,Reflection (physics) ,Thin film ,0210 nano-technology ,Refractive index ,Civil and Structural Engineering ,Visible spectrum - Abstract
Spectroscopic ellipsometry is a powerful technique for determining optical properties of any thin surface. A method for characterizing optical properties of warm asphalt binder using spectroscopic ellipsometry along with associated results has been presented in this paper. Thin films of warm asphalt binders were produced using LEADCAP and Sasobit and characterized using a variable angle spectroscopic ellipsometry. Refractive index and extinction coefficient of each of the samples (original and aged) were extracted from model fitted spectra. Clear variation in refractive index and extinction coefficient was observed among the samples before and after aging. The samples were found to be highly reflective with refractive index ‘n’ in the range 1.55–1.62 and extinction coefficient ‘k’ in the range of 0.01–0.06, both before and after aging. Reflectivity of PG 64-22 with LEADCAP exhibited the highest refractive index and the lowest extinction coefficient in visible wavelength of light among the samples. The results indicated that the highest reflection of visible light can be observed from LEADCAP-modified binder. Cracking properties and absorption coefficient of the binders are observed to have a correlation. The method reported here can be applied to any type of asphalt binder to determine its light absorption and reflection characteristics for a wide range of wavelength.
- Published
- 2019
37. Laboratory Characterization of Asphalt Binders Modified with Styrene Butadiene Rubber (SBR)
- Author
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Navid Hemmati, Jihyeon Yun, Mithil Mazumder, Moon-Sup Lee, and Soon-Jae Lee
- Subjects
Technology ,Microscopy ,QC120-168.85 ,QH201-278.5 ,SBR ,PMA ,rutting ,viscosity ,fatigue ,Engineering (General). Civil engineering (General) ,Article ,TK1-9971 ,Descriptive and experimental mechanics ,General Materials Science ,Electrical engineering. Electronics. Nuclear engineering ,TA1-2040 - Abstract
The study describes the laboratory assessment (physical and rheological properties) of the binders (PG 64-22 and PG 76-22) modified with Styrene Butadiene Rubber (SBR), and a comprehensive comparison between these two modified binder types. PG 64-22 and PG 76-22 were used as base binders. Both of the base binders were blended with SBR at four different percentages of content (0%, 4%, 6%, and 8% by the weight of the binder). The base and modified binders were artificially short-term and long-term aged using a rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were conducted on the SBR modified binder using rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR). In depth rutting performance was investigated using Multiple Stress Creep Recovery (MSCR). The results of this study indicated that (1) the addition of SBR into both binders increased the viscosity and polymer modified asphalt (PMA) binders observed to have more significant effect on its viscosity property; (2) the higher the SBR content, the better the rutting resistance of the binder and it is observed that the effect is prominent on the control binder; (3) MSCR test results showed that the SBR modified binders improved the binder percentage recovery and found to have a more significant effect on the PG 76-22 binder compared to PG 64-22; and (4) both the control PG 64-22 and PMA PG 76-22 binders resulted in similar trends on the cracking properties and were found to have insignificant effects due to the addition of an SBR modifier.
- Published
- 2021
38. Salix purpurea and Eleocharis obtusa Rhizospheres Harbor a Diverse Rhizospheric Bacterial Community Characterized by Hydrocarbons Degradation Potentials and Plant Growth-Promoting Properties
- Author
-
Fahad Alotaibi, Soon-Jae Lee, Marc St-Arnaud, and Mohamed Hijri
- Subjects
plant growth promoting rhizobacteria ,petroleum hydrocarbon-degrading bacteria ,Microbacterium ,polycyclic aromatic hydrocarbons ,Bulk soil ,Plant Science ,phytoremediation ,010501 environmental sciences ,Rhizobacteria ,01 natural sciences ,Article ,Eleocharis ,03 medical and health sciences ,Botany ,anatomy_morphology ,Ecology ,Ecology, Evolution, Behavior and Systematics ,030304 developmental biology ,0105 earth and related environmental sciences ,Salix ,0303 health sciences ,Rhizosphere ,biology ,food and beverages ,15. Life on land ,biology.organism_classification ,Holobiont ,Phytoremediation ,13. Climate action ,QK1-989 ,alkanes ,Stenotrophomonas ,Bacteria - Abstract
Phytoremediation, a method of phytomanagement using the plant holobiont to clean up polluted soils, is particularly effective for degrading organic pollutants. However, the respective contributions of host plants and their associated microbiota within the holobiont to the efficiency of phytoremediation is poorly understood. The identification of plant-associated bacteria capable of efficiently utilizing these compounds as a carbon source while stimulating plant-growth is a keystone for phytomanagement engineering. In this study, we sampled the rhizosphere and the surrounding bulk soil of Salixpurpurea and Eleocharis obusta from the site of a former petrochemical plant in Varennes, QC, Canada. Our objectives were to: (i) isolate and identify indigenous bacteria inhabiting these biotopes, (ii) assess the ability of isolated bacteria to utilize alkanes and polycyclic aromatic hydrocarbons (PAHS) as the sole carbon source, and (iii) determine the plant growth-promoting (PGP) potential of the isolates using five key traits. A total of 438 morphologically different bacterial isolates were obtained, purified, preserved and identified through PCR and 16S rRNA gene sequencing. Identified isolates represent 62 genera. Approximately, 32% of bacterial isolates were able to utilize all five different hydrocarbons compounds. Additionally, 5% of tested isolates belonging to genera Pseudomonas, Acinetobacter, Serratia, Klebsiella, Microbacterium, Bacillus and Stenotrophomonas possessed all five of the tested PGP functional traits. This culture collection of diverse, petroleum-hydrocarbon degrading bacteria, with multiple PGP traits, represents a valuable resource for future use in environmental bio- and phyto-technology applications.
- Published
- 2021
39. Evaluation of Petroleum Resin in Rubberized Asphalt Binder
- Author
-
Soon-Jae Lee, Moon-Sup Lee, Hyun Hwan Kim, and Mithil Mazumder
- Subjects
Materials science ,CRM binder ,Rheometer ,Geography, Planning and Development ,cracking ,TJ807-830 ,Management, Monitoring, Policy and Law ,TD194-195 ,PR ,rutting ,Renewable energy sources ,chemistry.chemical_compound ,Crumb rubber ,GE1-350 ,Composite material ,Rubberized asphalt ,Environmental effects of industries and plants ,Renewable Energy, Sustainability and the Environment ,MSCR ,Environmental sciences ,Cracking ,Creep ,chemistry ,Asphalt ,Petroleum resin ,Dynamic shear rheometer - Abstract
The crumb rubber modified (CRM) binder was evaluated considering the general operating temperatures of high, intermediate, and low temperatures. CRM binders were produced with four different contents (0, 5, 10, and 15%) using the base asphalt binder (PG64-22). Then, they were artificially aged by a rolling thin-film oven (RTFO) and pressure aging vessel (PAV). Superpave binder tests using a rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR) was applied to characterize the performance of the original and aged binders. Multiple stress creep recovery (MSCR) tests were also performed for deeper rutting characterization. The results of this study are as follows: (1) the presence of PR increases the binder viscosity, (2) the integration of CRM greatly improved the rutting resistance of the binder, and it was found that PR also improved the rutting characteristics, and (3) it is observed that PR is detrimental to the cracking properties of CRM binders.
- Published
- 2021
40. Generation of disproportionate nuclear genotype proportions in Rhizophagus irregularis progeny causes allelic imbalance in gene transcription
- Author
-
Chanz Robbins, Joaquim Cruz Corella, Consolée Aletti, Réjane Seiler, Ivan D. Mateus, Soon‐Jae Lee, Frédéric G. Masclaux, and Ian R. Sanders
- Subjects
Physiology ,AMF genetics, arbuscular mycorrhiza, plant production, plant symbiosis, Rhizophagus irregularis ,Plant Science - Abstract
Arbuscular mycorrhizal fungi (AMF) form mutualisms with most plant species. The model AMF Rhizophagus irregularis is common in many ecosystems and naturally forms homokaryons and dikaryons. Quantitative variation in allele frequencies in clonally dikaryon offspring suggests they disproportionately inherit two distinct nuclear genotypes from their parent. This is interesting, because such progeny strongly and differentially affect plant growth. Neither the frequency and magnitude of this occurrence nor its effect on gene transcription are known. Using reduced representation genome sequencing, transcriptomics, and quantitative analysis tools, we show that progeny of homokaryons and dikaryons are qualitatively genetically identical to the parent. However, dikaryon progeny differ quantitatively due to unequal inheritance of nuclear genotypes. Allele frequencies of actively transcribed biallelic genes resembled the frequencies of the two nuclear genotypes. More biallelic genes showed transcription of both alleles than monoallelic transcription, but biallelic transcription was less likely with greater allelic divergence. Monoallelic transcription levels of biallelic genes were reduced compared with biallelic gene transcription, a finding consistent with genomic conflict. Given that genetic variation in R. irregularis is associated with plant growth, our results establish quantitative genetic variation as a future consideration when selecting AMF lines to improve plant production.
- Published
- 2021
41. Economic Analysis of Crack Treatment Methods Using HDM-III Modeling
- Author
-
Hyun Hwan Kim, Moon-Sup Lee, Soon-Jae Lee, and Mithil Mazumder
- Subjects
business.industry ,Pavement maintenance ,Treatment method ,02 engineering and technology ,Structural engineering ,Net present value ,020303 mechanical engineering & transports ,0203 mechanical engineering ,Initial cost ,Long period ,Economic analysis ,Capital cost ,Unit cost ,business ,Civil and Structural Engineering ,Mathematics - Abstract
Crack sealing treatment includes the use of a router to create a reservoir on the intended cracks, whereas crack filling is given without any modification to the crack wall. With sealing treatment the pavement can have longer service period because of its good adhesion and cohesion performance. However, the initial cost of sealing is higher due to the use of extra material, equipment and labor. As a result, the aim of this study is to investigate the long-term cost-effectiveness in between these two treatment techniques in Texas and to observe if the longer service period can compensate the higher initial cost of sealing treatment. For this purpose, the initial cost inputs have been identified and a highway design and maintenance standard model (HDM-III) used to evaluate the most cost-effective pavement maintenance between crack sealing and filling treatment over a 25-year analysis period. Agency, capital and net present value have been calculated by using HDM-III based upon average daily traffic (ADT), altitude and road length. The results of this study indicated that (1) crack sealing is more cost-effective pavement maintenance compared to crack filling over a long period of time; (2) agency cost can be reduced by 15% and 14% based on ADT and road length analysis, respectively, by implementing crack sealing treatment; (3) capital cost in terms of ADT and road length with crack sealing maintenance can be saved by 24% and 19%, respectively; (4) the net present value with crack sealing treatment after a 25-year analysis period is higher for ADT and road length compared to crack filling by 18% and 19%, respectively; (5) the cost-effective resealing interval years of 5 years is proposed when the unit cost of routing increased by 25%.
- Published
- 2019
42. Performance evaluation of polymer modified asphalt (PMA) binders containing ground tire rubber (GTR)
- Author
-
Soon-Jae Lee, Moon-Sup Lee, and Hyun Hwan Kim
- Subjects
050210 logistics & transportation ,Materials science ,Rut ,Rheometer ,05 social sciences ,0211 other engineering and technologies ,02 engineering and technology ,Viscosity ,Cracking ,Natural rubber ,Creep ,Mechanics of Materials ,Asphalt ,visual_art ,021105 building & construction ,0502 economics and business ,Dynamic shear rheometer ,visual_art.visual_art_medium ,Composite material ,Civil and Structural Engineering - Abstract
The study presents an experimental evaluation of performance properties of rubberized polymer modified asphalt (PMA) binders to compare two types of ground tire rubber (GTR): normal and treated. Styrene-butadiene-styrene (SBS) modified asphalt binder (PG 76-22) is used as a base PMA binder to produce rubberized PMA binder. The rubberized PMA binders were artificially short-term and long-term aged using the rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were carried out on the binders through the rotational viscometer (RV), the dynamic shear rheometer (DSR), and the bending beam rheometer (BBR). Additionally, the multiple stress creep recovery (MSCR) test was accomplished to investigate the rutting properties. In general, the results of this study indicated that (1) the viscosity properties are found to be dependent on GTR types and amounts, as expected, (2) the rutting properties of PMA binders are expected to be improved through the use of GTR, (3) the addition of GTR is observed to be effective in improving the cracking performances of PMA binder, and (4) in general, the PMA binders with treated GTR showed better performance properties, compared to the PMA binders with normal GTR.
- Published
- 2019
43. 고령층의 민영건강보험 수요결정요인과 잠재적 수요 분석
- Author
-
Sung-ho Kang, Soon-Jae Lee, and Kim Daehwan
- Abstract
본 연구는 민영건강보험 수요를 결정하는 요인과 고령층의 잠재적 민영건강보험 수요를 추정하고 있다. 이에 의하면 민영건강보험 수요를 결정하는 주요 요인은 소득과 연령이며, 소득이 증가할수록 보험수요는 증가하는 반면 연령이 증가하면 보험수요는 감소하는 것으로 분석되었다. 이는 소득이 줄어드는 고령기에는 보험수요가 급격히 줄어들게 되고, 특히 저소득 노인의 경우 실제 보험수요가 잠재적 수요 수준에 못 미칠 수 있음을 의미한다. 본 연구에서 추정된 잠재적 민영건강보험료 수준은 월평균 11만 6천 원(보험료율 5.9%)으로 노인의 6.1%만 이를 충족하였다. 미충족자만을 대상으로 미충족갭률을 비교한 결과, 비노인은 67.1%, 노인은 91.7%로 나타났으며, 고연령화가 진행될수록 미충족갭률이 높아질 것으로 우려된다. 우리나라의 높은 노인빈곤율을 고려할 때 독일에서와 같이 근로기간 동안 보험료를 미리 적립하고 소득이 감소하는 은퇴기간에는 보험료 부담을 경감하는 평준보험료 방식(고령화적립금)을 고려할 필요가 있겠다.
- Published
- 2019
44. Effect of Processed Oil on Asphalt Binder Properties
- Author
-
Navid Hemmati, Jihyeon Yun, Hyunhwan Kim, Moon-Sup Lee, and Soon-Jae Lee
- Subjects
General Materials Science ,processed oil ,viscosity ,rutting ,fatigue ,thermal cracking - Abstract
This study investigates the effectiveness of processed oil in the modification of PG 64-22 and PG 76-22 by assessing their physical and rheological properties, and multiple comparison was conducted between the two binders. The base binders PG 64-22 and PG 76-22 were blended with processed oil at four different percentages of contents (3%, 6%, 9% and 12% by the weight of the binder) and compared with the control binder in each test. The base and modified binders were artificially short-term and long-term aged using a rolling thin film oven (RTFO) and pressure aging vessel (PAV) procedures. Superpave binder tests were performed on the modified binders by applying a rotational viscometer (RV), dynamic shear rheometer (DSR), and bending beam rheometer (BBR). The comparisons and results presented in this study indicate that (1) the processed oil has a significant effect on the binders’ viscosity, which changes with respect to the increment of processed oil content. The viscosity of both modified binders decreased with the addition of 3, 6, 9 and 12% processed oil; (2) the performed DSR test showed that the addition of processed oil had a negative effect on the rutting resistance for both binders, since in PG 64-22, G*/Sin δ values decreased by 55, 65, 75 and 83% with the addition of 3, 6, 9 and 12% processed oil, respectively, while a decrement of G*/Sin δ of 24, 45, 58 and 65% with the addition of 3, 6, 9 and 12% processed oil was observed in PG 76-22; meanwhile, the fatigue cracking performance was improved and was found to be effective, while G* Sin δ in PG76-22 decreased by 9, 30, 36, and 52% and in PG 64-22 by 27, 44, 53, and 67% with the addition of 3, 6, 9 and 12% processed oil; (3) the results from the BBR test indicate significant improvement in the thermal cracking properties of the binders. The addition of 3, 6, 9 and 12% processed oil resulted in a decrease in the stiffness of both the PG 64-22 and PG 76-22 binders, with a positive effect consequently being observed on the m-values of the binders.
- Published
- 2022
45. Effect of blending time on viscosity of rubberized binders with wax additives
- Author
-
Mithil Mazumder, Moon-Sup Lee, Hyun Hwan Kim, and Soon-Jae Lee
- Subjects
Wax ,Materials science ,lcsh:TE1-450 ,0211 other engineering and technologies ,02 engineering and technology ,Rotational viscometer ,021001 nanoscience & nanotechnology ,Viscosity ,Mechanics of Materials ,visual_art ,Rotational viscosity ,021105 building & construction ,visual_art.visual_art_medium ,Crumb rubber ,Composite material ,0210 nano-technology ,lcsh:Highway engineering. Roads and pavements ,Civil and Structural Engineering - Abstract
The effect of blending time on the viscosity of rubberized binder with wax additives was evaluated through the rotational viscometer at 135 °C and 120 °C. The 10% crumb rubber modified (CRM) binders were produced with four blending periods (1, 30, 60, and 90 min), and then mixed with two commercial wax additives. Three different testing periods of 30, 120, and 240 min were applied to the rotational viscosity test to evaluate the viscous properties depending on the blending time. From the results, it is concluded that (1) the addition of wax additives can significantly decreases the binder viscosity, (2) all the viscosity values of CRM binders are observed to increase after certain time, regardless of the addition of wax additives, (3) CRM mixes with wax additives are expected to have a better haul management, based on the less viscosity change, (4) in general, the effect of blending time at 177 °C on the viscous property of CRM binder is found to be insignificant. Keywords: CRM, Wax additive, Blending time, Rotational viscosity
- Published
- 2018
46. SEM and ESEM techniques used for analysis of asphalt binder and mixture: A state of the art review
- Author
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Ahmed Wajahat Ali, Raju Ahmed, Mithil Mazumder, and Soon-Jae Lee
- Subjects
Materials science ,Scanning electron microscope ,0211 other engineering and technologies ,02 engineering and technology ,Building and Construction ,State of the art review ,021001 nanoscience & nanotechnology ,Microstructure ,Rheology ,Asphalt ,021105 building & construction ,General Materials Science ,Sample preparation ,Composite material ,0210 nano-technology ,Dispersion (chemistry) ,Environmental scanning electron microscope ,Civil and Structural Engineering - Abstract
This paper reviews techniques and analyses performed on microstructure of the asphalt binder and mixture using Scanning Electron Microscopy (SEM) and Environmental Scanning Electron Microscopy (ESEM). An extensive insight on the SEM and ESEM principle and techniques, different sample preparation methods and instrument techniques for capturing the micromorphology of the binder and mixture have been presented. The difference between SEM and ESEM in terms of challenges and limitation regarding the analysis of bitumen has been explained. In depth discussions on the surface properties, fracture morphology, network structure, dispersion, phase morphology, structural and strength mechanism, adhesion, deform mechanism and the formation of fibril structures of asphalt binder and mixture have been provided. Recommendations and useful techniques are outlined for future research to obtain any correlation between the microstructure and physical/rheological properties of the asphalt binder/mixture.
- Published
- 2018
47. Reciprocal recombination reflects sexual reproduction in symbiotic arbuscular mycorrhizal fungi
- Author
-
Soon-Jae Lee, Mam M. S. Ndiaye, Ben Auxier, Ian R. Sanders, Ivan D. Mateus, and Joaquim Cruz
- Subjects
Genetics ,fungi ,Locus (genetics) ,Gene conversion ,Mating ,Biology ,Monokaryon ,Orthologous Gene ,Parasexual cycle ,Dikaryon ,Sexual reproduction - Abstract
Arbuscular mycorrhizal fungi (AMF) are part of the most widespread fungal-plant symbiosis. They colonize at least 80% of plant species, promote plant growth and plant diversity. These fungi are multinucleated and contain either one or two haploid nuclear genotypes (monokaryon and dikaryon) identified by the alleles at a putative mating-type locus. This taxon has been considered as an ancient asexual scandal because of the lack of observable sexual structures. Despite identification of a putative mating-type locus and functional activation of genes related to mating when two isolates co-exist, it remains unknown if AMF take part in a mainly sexual life cycle.We used publicly available genome sequences to test if dikaryon genomes display signatures of sexual reproduction in the form of reciprocal recombination patterns, or if they display signatures of parasexual reproduction involving gene conversion.We used short-read and long-read sequence data to identify nucleus genotype-specific haplotypes within dikaryons and then compared them to orthologous gene sequences from related monokaryon isolates displaying the same putative MAT-types. We observed that these genotype-specific haplotypes display reciprocal recombination and not gene conversion.These results are consistent with a sexual origin of the dikaryon rather than a parasexual origin and provides an important step to understand the life cycle of these globally important symbiotic fungi.
- Published
- 2021
48. Polarization Control of Deterministic Single-Photon Emitters in Monolayer WSe
- Author
-
Jae-Pil, So, Kwang-Yong, Jeong, Jung Min, Lee, Kyoung-Ho, Kim, Soon-Jae, Lee, Woong, Huh, Ha-Reem, Kim, Jae-Hyuck, Choi, Jin Myung, Kim, Yoon Seok, Kim, Chul-Ho, Lee, SungWoo, Nam, and Hong-Gyu, Park
- Abstract
Single-photon emitters, the basic building blocks of quantum communication and information, have been developed using atomically thin transition metal dichalcogenides (TMDCs). Although the bandgap of TMDCs was spatially engineered in artificially created defects for single-photon emitters, it remains a challenge to precisely align the emitter's dipole moment to optical cavities for the Purcell enhancement. Here, we demonstrate position- and polarization-controlled single-photon emitters in monolayer WSe
- Published
- 2021
49. The effects of mycorrhizal colonization on phytophagous insects and their natural enemies in soybean fields
- Author
-
Colin Favret, Soon-Jae Lee, Mohamed Hijri, and Élisée Emmanuel Dabré
- Subjects
0106 biological sciences ,Rhizophagus irregularis ,Empoasca ,Plant Science ,01 natural sciences ,Biochemistry ,Mycorrhizae ,Bradyrhizobium ,Amino Acids ,2. Zero hunger ,0303 health sciences ,Multidisciplinary ,biology ,Ecology ,Organic Compounds ,Eukaryota ,food and beverages ,Agriculture ,Insects ,Chemistry ,Plant-Insect Interactions ,Physical Sciences ,Medicine ,Agrochemicals ,Research Article ,Arthropoda ,Ecological Metrics ,Science ,Glycine ,Crops ,Rhizobacteria ,010603 evolutionary biology ,03 medical and health sciences ,Rhizophagus (fungus) ,Plant-Animal Interactions ,Botany ,Animals ,Soybean aphid ,Fertilizers ,Microbial inoculant ,030304 developmental biology ,Plant Ecology ,Ecology and Environmental Sciences ,Organic Chemistry ,Fungi ,Soybeans ,fungi ,Organisms ,Chemical Compounds ,Biology and Life Sciences ,Proteins ,Species Diversity ,biology.organism_classification ,Invertebrates ,Aliphatic Amino Acids ,Aphids ,Zoology ,Entomology ,Bradyrhizobium japonicum ,Crop Science - Abstract
The use of belowground microorganisms in agriculture, with the aim to stimulate plant growth and improve crop yields, has recently gained interest. However, few studies have examined the effects of microorganism inoculation on higher trophic levels in natural conditions. We examined how the diversity of phytophagous insects and their natural enemies responded to the field-inoculation of soybean with a model arbuscular mycorrhizal fungus (AMF), Rhizophagus irregularis, combined with a nitrogen-fixing bacterium, Bradyrhizobium japonicum, and a plant growth-promoting bacterium, Bacillus pumilus. We also investigate if the absence or presence of potassium fertilizer can affect this interaction. We found an increase in the abundance of piercing-sucking insects with the triple inoculant irrespective of potassium treatment, whereas there were no differences among treatments for other insect groups. A decrease in the abundance of the soybean aphid, Aphis glycines, with the double inoculant Rhizophagus + Bradyrhizobium was observed in potassium enriched plots and in the abundance of Empoasca spp. with potassium treatment independent of inoculation type. Although it was not possible to discriminate the mycorrhization realized by inoculum from that of the indigenous AMF in the field, we confirmed global negative effects of overall mycorrhizal colonization on the abundance of phytophagous piercing-sucking insects, phytophagous chewing insects, and the alpha diversity of phytophagous insects. In perspective, the use of AMF/Rhizobacteria inoculants in the field should focus on the identity and performance of strains to better understand their impact on insects.
- Published
- 2021
50. Laboratory Evaluation of Sustainable PMA Binder Containing Styrene-Isoprene-Styrene (SIS) and Thermoplastic Polyurethane
- Author
-
Hyun Hwan Kim, Mithil Mazumder, Soon-Jae Lee, and Moon-Sup Lee
- Subjects
Materials science ,Geography, Planning and Development ,cracking ,lcsh:TJ807-830 ,0211 other engineering and technologies ,Compaction ,lcsh:Renewable energy sources ,02 engineering and technology ,Management, Monitoring, Policy and Law ,rutting ,Styrene ,Viscosity ,chemistry.chemical_compound ,Thermoplastic polyurethane ,Rheology ,TPU ,021105 building & construction ,Composite material ,lcsh:Environmental sciences ,lcsh:GE1-350 ,Renewable Energy, Sustainability and the Environment ,lcsh:Environmental effects of industries and plants ,021001 nanoscience & nanotechnology ,SIS ,Cracking ,lcsh:TD194-195 ,Creep ,chemistry ,Asphalt ,viscosity ,0210 nano-technology - Abstract
In this study, thermoplastic polyurethane (TPU) and styrene-isoprene-styrene (SIS) were utilized to enhance asphalt binder properties. Superpave asphalt binder tests and multiple stress creep recovery (MSCR) were conducted to evaluate the physical and rheological performance (viscosity, rutting, and cracking properties) of the asphalt binders before and after short-term aging and after the long-term aging process. The results showed that (i) TPU has a positive effect on workability, including the mixing and compaction processes, which was evident from the reduced binder viscosity, (ii) asphalt binders with TPU and SIS showed better rutting resistance compared to the SIS binders without TPU, (iii) the cracking resistance of asphalt binders was found to be improved significantly with the addition of TPU, and (iv) TPU has the potential to be considered as a sustainable polymer modifier for producing bearable asphalt binders by improving rutting and crack resistance without increasing the melting temperature of the asphalt binders.
- Published
- 2020
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